Thiol-Modulation-Induced Mesoporous Nanosheets with an Alloy/Intermetallic Heterophase for Efficient Electrochemical Ethylene Glycol-Assisted Water Splitting

Abstract

Ligand modification has been widely utilized to tune the coordination environment of active sites in noble metal-based electrocatalysts to enhance their catalytic activity and selectivity. However, the ligand-induced structure transition of the catalyst and its effect on performance is not clear. In this study, a thiol modification strategy is developed to prepare sulfur-capped mesoporous PtPbBi nanosheets (S-PtPbBi MNSs) with an alloy/intermetallic compound heterophase and inhomogeneous tensile strain (≈3%). The obtained S-PtPbBi MNSs exhibit excellent electrocatalytic performance for ethylene glycol oxidation reaction (EGOR), achieving a Faradic efficiency of up to 92% in converting EG to glycolic acid. In EG-assisted electrochemical water splitting, S-PtPbBi MNSs only require a low cell voltage of 0.60 V to achieve a current density of 10 mA cm⁻². The anion exchange membrane electrolyzer utilizing S-PtPbBi MNSs catalyst can drive a current density of 500 mA cm⁻² at 1.63 V, along with exceptional stability for 200 h. Density functional theory calculations reveal that thiol modification facilitates the adsorption of reactants and enhances the electron transfer between the catalyst and key intermediate. This work provides deep insights into ligand modification-induced construction of novel catalysts and creates new opportunities for small molecule-assisted water splitting for efficient production of hydrogen.